A SENSITIVE HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC METHOD FOR DETECTING SULFONAMIDE RESIDUES IN SWINE SERUM AND TISSUES AFTER FLUORESCAMINE DERIVATIZATION

A highly sensitive and rapid high-performance liquid chromatographic m ethod for determining sulfonamides (sulfadiazine, sulfamethazine, sulf amonomethoxine, sulfamethoxazole and sulfadimethoxine) in swine serum and tissues is described. The sulfonamides were extracted from the sam ples, derivatized with fluorescamine, chromatographed on a Nova-Pak C- 18 column using acetonitrile-10 mM potassium phosphate (30:70, v/v) as the mobile phase and detected spectrofluororimetrically (excitation 3 90 nm, emission 475 nm). The retention times were 7.1 to 18.2 min and there was no interference from any co-extractives. The detection limit for each standard sulfonamide solution was 0.1 ng/ml and their calibr ation curves were linear between 1 and 100 ng/ml. In the presence of s ulfadiazine as an internal standard, sulfonamide recovery from spiked serum, muscle, liver and kidney samples (10 ng/ml) was 94.0 +/- 4.7 to 97.3 +/- 5.9%, 58.5 +/- 3.1 to 73.9 +/- 5.7 %, 65.9 +/- 7.1 to 86.9 /- 10.6% and 86.2 +/- 4.0 to 92.8 +/- 6.4% respectively.